St. John’s Wort is a commonly found herbal medication which is useful for the treatment of depression and as an antiviral agent. The name St. John’s wort is so called because it’s flowers blossoms around St. John’s day which is celebrated on the 24th of June. It is also known as klamath weed, amber touch-and-heal, rosin rose, goatweed and millepertuis. The major chemical constituent of St. John’s Wort is hypericin which is a phenolic glycoside. St. John’s wort is also included in the British Pharmacopoeia (B.P) and in the United States Pharmacopoeias (USP) as treatment for depression.
St. John’s Wort (Anthraquinones)
|Biological Source||Dried aerial parts of Hypericum perforatum|
|Geographical Source||Perennial plant native to Europe. Through colonization it is now also found in USA and parts of Canada and Australia and was initially thought to be a weed.|
|Chemistry||St. John’s Wart consists of a variety of constituents including napthodianthrones (less than 0.1%-0.15%), flavonoids, phloroglucinols and essential oils.
Napthodianthrones-Hypericin(reddish pigment found in concentration of 0.02% -2.5%) and Pseudohypericin are the anthroquinones present. Also present are emodin-anthranol, cyclo-pseudohypericin, isohypericin and protohypericin.
Essential oils are present in concentrations of 0.05%-0.9%. It consists of mono- and sesquiterpenes.
|Chemical Tests||Anthraquinones are generally orange-red compounds which can be extracted and their UV absorbance wavelengths can be checked. Hypericin has a unique UV-visible absorption spectrum and absorbs light with a λmax of 598nm.|
|Adulterants/Allied drugs/ Substitutes||St. John’s wort is a dietary supplement in the USA and is therefore not regulated by the FDA. The hypericin constituent in the formulations can vary between 47% to 165% of labeled hypericin concentrations. Other constituents also vary to great extent depending upon harvest time of the medicine. Thus one should be advised even though the medication may not contain adulterants, activity may change from one formulation to another.|
|Uses||St.John’s wort has potential antidepressant and antiviral effects. It is also useful as an antibacterial, anti-inflammatory and is known to have wound-healing and skin-healing properties|
|Other Notes (life cycle, extraction, pharmacology etc.)||Proposed Mechanism of Action:
- Trease and Evans’ Pharmacognosy, 16e (Evans, Trease and Evans Pharmacognosy)
Elsevier: New York, 2009.
- Ara DerMarderosian, et. al. The Review of Natural Products 4th Edition.
- Kokate, C. K.; Gokhale, S. B.; Purohit, A. P. A textbook of Pharmacognosy, 29th ed.; Nirali Prakashan: Pune, 2009.